FreeBSD 10.4-RELEASE Errata

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Last modified on 2017-10-03 19:08:16 by gjb.

Abstract

This document lists errata items for FreeBSD 10.4-RELEASE,
containing significant information discovered after the
release or too late in the release cycle to be otherwise
included in the release documentation. This information
includes security advisories, as well as news relating to the
software or documentation that could affect its operation or
usability. An up-to-date version of this document should
always be consulted before installing this version of
FreeBSD.

This errata document for FreeBSD 10.4-RELEASE will be
maintained until FreeBSD 10.4-RELEASE reaches
end-of-life.

1.Â Introduction

This errata document contains “late-breaking
news” about FreeBSD 10.4-RELEASE Before installing this
version, it is important to consult this document to learn about
any post-release discoveries or problems that may already have
been found and fixed.

Any version of this errata document actually distributed
with the release (for example, on a CDROM distribution) will be
out of date by definition, but other copies are kept updated on
the Internet and should be consulted as the “current
errata” for this release. These other copies of the
errata are located at https://www.FreeBSD.org/releases/, plus any
sites which keep up-to-date mirrors of this location.

Source and binary snapshots of FreeBSD 10.4-STABLE also
contain up-to-date copies of this document (as of the time of
the snapshot).

3.Â Errata Notices

4.Â Open Issues

FreeBSD/i386 10.4-RELEASE running as a guest
operating system on VirtualBox
can have a problem with disk I/O access. It depends on some
specific hardware configuration and does not depend on a
specific version of VirtualBox or
host operating system.

It has been reported that instability may be present on
virtual machines running on other hypervisors, such as Xen
or KVM.

It causes various errors and makes FreeBSD quite unstable.
Although the cause is still unclear, disabling unmapped I/O
works as a workaround. To disable it, choose
Escape to loader prompt in the boot menu
and enter the following lines from loader(8) prompt,
after an OK:

set vfs.unmapped_buf_allowed=0
boot

Note that the following line has to be added to
/boot/loader.conf after a boot. It
disables unmapped I/O at every boot:

vfs.unmapped_buf_allowed=0

FreeBSD/i386Â 10.4-RELEASE installed on ZFS
may crash during boot when the ZFS pool mount is attempted
while booting an unmodified GENERIC
kernel.

As described in /usr/src/UPDATING
entry 20121223, rebuilding the kernel
with options KSTACK_PAGES=4 has been
observed to resolve the boot-time crash. This, however, is
not an ideal solution for inclusion in the
GENERIC kernel configuration, as
increasing KSTACK_PAGES implicitly
decreases available usermode threads in an environment that
is already resource-starved.

Taking into account the heavy resource requirements of
ZFS, in addition to the i386-specific tuning
requirements for general workloads, using ZFS with the
FreeBSD/i386Â GENERIC kernel
is strongly discouraged.

If installing FreeBSD/i386 on ZFS, it is possible to
configure the system after installation to increase the
KSTACK_PAGES.

When prompted by bsdinstall(8) to perform
additional post-installation configuration to the system,
select [Â YESÂ ].

This procedure requires the system sources available
locally. If the System source code
distribution was not selected during installation, it can
be obtained using svnlite:

Warning:

It is extremely important to take note that, by
default, freebsd-update(8) will install the
GENERIC kernel configuration, and
as such, freebsd-update(8) consumers are strongly
encouraged to avoid FreeBSD-provided kernel binary upgrades
with such configurations.